Contents
Overview
How glass lifting works
Glass lifting is moving large glass panels with equipment that grips the face or the edge of the glass, so nobody has to carry its weight. On site that means a vacuum lifter or a glass clamp hung from a crane, or a glazing robot that drives the panel up to the opening and offers it into place.
In short
- Float glass (ordinary flat glass) weighs about 2.5 kg per square metre for every millimetre of thickness, so a panel’s weight follows from its area and its thickness.
- The crane carries the lifter as well as the glass, so the lifter’s own weight goes into the crane’s load.
- Nobody stands or walks under a panel hanging from a vacuum lifter, and the plan closes off the ground below its path.
- In Great Britain, HSE’s guidance sets a 6-monthly thorough examination for a vacuum lifter moved from crane to crane, and a 12-monthly one, or a written scheme, for a lifter fixed permanently to its crane.
We take on glass lifts with mobile cranes through our crane hire and contract lifting service. On a contract lift, our own appointed person plans the lift and writes the lift plan.
Sources
Where this guidance comes from
In Great Britain, the law on planning a lift and examining the equipment is the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER), and HSE’s guidance on vacuum lifting equipment explains how it applies to vacuum lifters. The rules on open edges and keeping people out of danger areas come from the Work at Height Regulations 2005. The Glass and Glazing Federation also publishes a code of practice on handling and storing glass on site.
Capacities, vacuum levels, working temperatures and weather limits are set by each maker and differ between products. Always use your own equipment’s figures and its maker’s instructions.
Equipment
Glass lifting equipment compared
The table sets the three kinds of equipment side by side, with one maker’s product as an example of each.
| Equipment | How it holds the glass | What lifts it | Example maker figure |
|---|---|---|---|
| Vacuum lifter | Rubber suction pads on the face of the glass, held by a vacuum pump | A crane, a mini crane or another lifting machine | Schmalz rates its VacuMaster Glass 600 at up to 600 kg |
| Glass clamp | Lined jaws gripping the edge of the panel | A crane or a forklift | Aardwolf gives its AL30AWJH clamp a working load limit (the heaviest load it is built to take) of 1,200 kg for glass up to 30 mm thick |
| Glazing robot | Vacuum pads on a hydraulic arm | The robot itself, driving on wheels or tracks | GMV’s Winlet glazing robots on wheels or tracks run from 375 kg to 1,000 kg |
Vacuum lifters
HSE separates two kinds. A vacuum lifting attachment grips the load while a separate machine, such as a crane, does the lifting. A vacuum lifting tube grips and lifts with the same unit. On a building site, glass is lifted with an attachment hung from a crane hook or with pads built into a glazing robot.
The pads hold only while the vacuum lasts. HSE’s guidance says a vacuum lifting attachment should have a vacuum indicator and a warning device, and makers set the vacuum the gauge must show before the load leaves the ground. Some lifters can also turn the panel: the VacuMaster Glass 600 can be swivelled through 90 degrees and turned through 360 degrees in 45-degree steps, both by hand, so a panel picked up flat from a stand can be stood upright for fitting.
HSE’s guidance also notes “additional requirements for tilting loads, eg glass handling”. The standard for lifting attachments used with cranes and hoists, vacuum lifters included, is BS EN 13155, and Schmalz says its VacuMaster Glass 600 is built to the German edition, DIN EN 13155.
Glass clamps
A glass clamp holds the panel by its edge. Aardwolf’s AL30AWJH, for example, uses gravity-assisted locking and rubber-coated jaws. Our guide to types of lifting clamp covers how clamps for steel plate and beams work.
Glazing robots
GMV’s Winlet robots drive under their own power and use hydraulics to lift and handle the glass. The operator works them from a remote control on a cable. The robot has to reach the opening itself, so its own lifting height and the ground it drives over decide where it can work.
The crane
Choosing the crane for a glass lift
Where the glass has to go up the outside of a building or over a roof, the vacuum lifter or clamp hangs from a crane. The crane is sized like any other, from the total weight at the radius it works at, with a boom long enough to clear whatever is in the way. Our guide What size crane do I need? explains the method, with the radius measured from the centre of the crane’s slew ring to the load’s centre of gravity at its furthest point.
The total weight is the glass plus the lifter and everything between it and the hook. Schmalz lists its VacuMaster Glass 600 at 66 kg to 86 kg, depending on how it is set up.
Smaller cranes do much of this work. A spider crane can work inside a building or on a roof, and the smallest models fit through a standard single door. A light truck crane has a long, light boom for placing glass and cladding at height on smaller sites. Heavier panels, or floors beyond a small crane’s reach, call for a larger mobile crane, such as a city crane (a compact mobile crane built for tight sites) or an all-terrain crane. Inside a building, where there is no room for outriggers, a pick and carry crane lifts on its wheels, and electric models produce no fumes.
A separate guide, How to Read a Crane Load Chart, covers reading the capacity off the chart.
Weight
How much a glass panel weighs
AGC, a float glass maker, gives the density of its float glass as 2,500 kg per cubic metre. That works out at 2.5 kg for every square metre of glass and every millimetre of thickness. Multiply the panel’s area in square metres by its thickness in millimetres, then by 2.5, to get its weight in kilograms.
| Glass thickness | Weight per square metre | A 3 m by 2 m panel |
|---|---|---|
| 6 mm | 15 kg | 90 kg |
| 10 mm | 25 kg | 150 kg |
| 12 mm | 30 kg | 180 kg |
| 19 mm | 47.5 kg | 285 kg |
A double glazed unit has two panes, so add their thicknesses together: a unit with two 10 mm panes has 20 mm of glass, or 50 kg per square metre. The frame and spacers add more, so plan with the weight the glass supplier gives for the finished unit wherever there is one.
Planning
Planning a glass lift
In Great Britain, regulation 8 of LOLER requires every lifting operation with lifting equipment to be properly planned by a competent person. The same regulation requires the lift to be supervised and carried out safely. Our guide What is a lift plan? sets out what the plan contains.
Weather
Vacuum pads need a clean surface to seal on. HSE warns that loose material on the load can let air in, and that this has caused loads to drop. Makers set their own limits on conditions: Aardwolf’s manual for its AEVGLP4-500 lifter says to keep the pads clean and free of dirt and oil, and to avoid using the lifter in rain, while Schmalz gives an operating range of 0 °C to 40 °C for the VacuMaster Glass 600.
A large panel also has a big flat face for the wind to push on. The lift plan sets the wind limit for the crane and that load together, from the makers’ figures, and records it in the method statement (the written sequence of work). Wind limits are the subject of a separate guide, Crane Wind Speed Limit: Lifting in Wind.
Exclusion zones
HSE’s guidance says vacuum lifting equipment is unsuitable where the load is likely to pass over people, or where a sudden fall of the load could have dangerous consequences. In Great Britain, regulation 11 of the Work at Height Regulations 2005 requires an area where a person at work could be struck by a falling object to be clearly marked and, so far as is reasonably practicable, fitted with devices, such as barriers, that keep unauthorised people out.
Edge protection
Glazing at height means working at an open edge of a floor or roof, where edge protection, the guard rails and toe boards along that edge, stops people falling. In Great Britain, regulation 6 of the Work at Height Regulations 2005 requires employers to take suitable and sufficient measures to prevent, so far as is reasonably practicable, anyone falling a distance liable to cause injury. Where a guard rail has to come out to let a panel in, the plan says who takes it out and puts it back, and how the glaziers are protected while it is out.
Example
An example glass lift (a made-up job)
This example is for an invented job: lifting one double glazed unit from a delivery stand in a site compound into a second floor opening, using a vacuum lifter on a spider crane. Every figure is a round number for illustration.
| Part of the plan | What this example says |
|---|---|
| The glass | A unit 3 m by 2 m with two 10 mm panes. At 2.5 kg per square metre per millimetre, 6 m² of 20 mm glass weighs 300 kg. The supplier gives 320 kg for the finished unit, so the plan uses 320 kg. |
| The lifter | A vacuum lifter weighing 80 kg, rated by its maker for more than 320 kg in every position the panel is turned through. |
| Load on the crane | The unit at 320 kg, the lifter at 80 kg and the hook and shackle at 20 kg, so the crane lifts 420 kg in total. |
| Crane and set-up | A spider crane in the compound, working at a radius of 8 m when the unit is at the opening. Its load chart shows more than 420 kg at 8 m, with the boom needed to reach the second floor. |
| Ground | Assessed by a competent person for the outrigger loads, with mats under each outrigger. |
| Weather | The lift goes ahead only in dry weather, within the lifter maker’s temperature range. The highest wind speed for the crane and this panel is recorded in the method statement. |
| Area under the load | The footpath between the compound and the building closed with barriers and signs, so nobody walks under the panel. |
| Edge protection | The guard rail across the opening is taken out only while the unit goes in, by the person named in the plan, and put back straight after. |
| Checks | Pads and warning devices checked at the start of the day, and the lifter’s last thorough examination report seen. |
| People | The appointed person wrote the plan, and the crane supervisor runs the lift and can stop it. Two glaziers at the opening receive the unit. |
| Sequence | Attach the pads to the unit on its stand and check the gauge shows the maker’s working vacuum. Lift, turn the unit upright and slew it to the opening. Set it on its supports and release the vacuum once it is secure. |
A real plan uses the unit’s actual weight, the lifter maker’s own ratings and the crane maker’s own figures, and the lift has to be planned by a competent person.
Inspection
Inspecting vacuum lifters under LOLER
HSE’s guidance sorts vacuum lifters by how they are fitted. One that can be fitted to and taken off a crane or other lifting equipment counts as an accessory for lifting. One built into a machine counts as lifting equipment. On that reading, the pads built into a glazing robot are lifting equipment too. A glass clamp hung from a crane hook fits LOLER’s definition of an accessory for lifting, equipment for attaching loads to machinery for lifting.
In Great Britain, regulation 9 of LOLER requires lifting equipment exposed to conditions that cause deterioration liable to make it dangerous to be thoroughly examined by a competent person. That means at least every 6 months for a lifting accessory and every 12 months for other lifting equipment, or at the intervals an examination scheme sets (a written scheme of examination drawn up by a competent person), and again after any exceptional circumstances liable to put its safety at risk. HSE’s guidance applies this to vacuum lifters in two groups. A vacuum lifting attachment used like a sling, moved between different lifting machines, is a lifting accessory and is examined every 6 months. One permanently fixed to a crane, gantry or similar is examined every 12 months or under a written scheme of examination.
Between examinations, HSE’s guidance asks for every pad to be checked and every warning device tested at the start of each shift or day, with pipes, connections, gauges and filters added to the checks each week. In Great Britain, LOLER also requires a hired lifter to come with physical evidence that its last thorough examination was carried out. Our guide What is a LOLER inspection? covers who carries out the examination and what the report contains, and Northern Ireland has its own equivalent regulations.
From our lifts
We ask for the weight of each panel from the glass supplier, and the make and model of the vacuum lifter, so we know its own weight and its rating in every position the panel turns through. We check the lifter’s last thorough examination report and test its warning device on the day. Then we walk the route from the delivery stand to the opening.
What catches people out is the opening. The panel arrives, the crane is set up, and the opening is smaller than the drawing or the guard rail across it is still bolted in place. Wet or dusty glass is the other one: the pads won’t seal properly, and the lift waits until the glass is clean and dry.
Send us the glass schedule early, with the size, thickness and weight of the largest panel and the floor it goes to. That one panel decides the lifter and the crane. Have the openings measured and the edge protection plan agreed before the delivery, so the glass goes straight from the lorry into the building.
Questions
Common questions
What is a glass lifter?
A glass lifter is a device that holds a glass panel so it can be lifted by machine. Most use suction pads kept under vacuum by a pump, and hang from a crane hook or form part of a glazing robot. Small hand-held suction cups lift light panes by hand. Edge clamps grip the panel’s edge instead of its face.
What is the best way to move large glass panels?
With mechanical equipment matched to the panel’s weight and route. A glazing robot suits openings it can drive up to and reach. For upper floors or over a roof, a vacuum lifter on a crane carries the panel up the outside. Either way, the lift is planned first, with the area under the glass kept clear.
How do you work out how much a glass panel weighs?
Work out the area in square metres, then allow 2.5 kg for each square metre per millimetre of thickness, which follows from AGC’s stated density of 2,500 kg per cubic metre for its float glass. A 2 m by 1 m pane 10 mm thick weighs about 50 kg. For a double glazed unit, add both panes and use the supplier’s weight.
Does a vacuum lifter need a LOLER inspection?
Yes. In Great Britain, HSE treats a vacuum lifter moved between lifting machines as a lifting accessory under LOLER, thoroughly examined by a competent person every 6 months. One fixed permanently to a crane is examined every 12 months or under a written scheme. HSE’s guidance also asks for pads and warning devices to be checked each day.
What happens if a vacuum lifter loses power?
In Great Britain, HSE’s guidance says a vacuum lifting attachment should warn the operator by sound and light if its vacuum pump fails and, wherever possible, have a vacuum reservoir that holds the load for at least 5 minutes after the pump stops. Makers add their own safeguards, such as the two separate vacuum circuits Schmalz builds into its VacuMaster Glass 600.
Can you lift glass over people?
No. In Great Britain, HSE’s guidance on vacuum lifting equipment says it is unsuitable where the load is likely to pass over people. The lift plan routes the panel away from anyone, and the Work at Height Regulations 2005 require danger areas to be marked, with barriers or other devices that keep unauthorised people out where reasonably practicable.
Can glass be lifted in the rain?
That depends on the lifter. Dirt on the glass can let air under the pads, and some makers rule out wet weather: Aardwolf tells users of its AEVGLP4-500 to avoid rain. Others set a temperature range, such as Schmalz’s 0 °C to 40 °C for the VacuMaster Glass 600. Follow your own lifter’s instructions, and record the limits in the lift plan.
Get help
Get help with a glass lift
Call us on 0800 008 6096 or email office@synergy-lifting.co.uk. Tell us the size and weight of the heaviest panel and the floor it goes to, and send photos or drawings showing where a crane could stand. We will quote for the glass lift.
Find out more about our crane hire and contract lifting service, or our lift and shift service for moving loads within a building.
Related
Find out more
Get a quote
Ready for a quote?
Send us the details and we will come back with a quote, usually the same day for a desktop survey.
Or call 0800 008 6096
